Power-operated portable tool



Dec. 25, 1951 w. H. DEAN PowER-oPERA-TED PORTABLE Toor.

5 Sheets-Sheet 2 Filed Dec. 17, 1949 I NVENTOR wl LL'HII H- DEAN ATTORNEY Dec. 25, 1951 w. H. DEAN PowER-oPERATED PORTABLE TooL .'5 Sheets-Sheet 5 Filed Dec.

INVENTOR Wl LL H. DEAN BY. jaa/wcm ATTORNEY y www N O A v w m G w/\ f n 4 E y f Patented Dec. 25, 1951 POWER-OPERATED PORTABLE TOOL William Henry Dean, Middleton Saint George, Darlington, England Application December 17, 1949, Serial No. 133,569l

` In Great Britain December 23, 1948 4 Claims.

This invention relates to power-operated portable tools of the kind driven by resilient means working in conjunction with power-driven reciprocating mechanism provided apart from the tool and coupled thereto by a exible drive.

The present invention has for its primary object to provide a working head having improved means for controlling the starting and stopping of the operative member of the head, said control means operating independently of the drive to the tool. Another object of the invention is to adapt the working head for use with a percussive operative member, such as a hammer for a rivet set, wall drill, scaling chisel or the like, or for use with a reciprocating operative member, such as a saw, shearing blade, punch or le. A further object of the invention is to improve the flexible drive to the working head whereby greater power may be transmitted to the operative member and the application of the tool to the work facilitated.

With the above and objects in view as will appear herein, my invention consists in the novel features of construction and the combination and arrangement of parts hereinafter described in detail and particularly set forth in the appended claims, reference being had to the accompanying drawings which illustrate portable tools embodying my invention and also the improved flexible connection between the reciprocating mechanism and the working head. In the drawings:

Figure 1 is a side elevation to a reduced scale of a portable tool in accordance with my invention, and

Figure 2 is an elevation looking on the lefthand end thereof.

. Figure 3 is a. sectional elevation of the working head of the tool tted with a percussive operative member, and

Figures 4 and 5 are similar sections on the line IV--IV in Fig. 3 showing the control means in their obstructive and non-obstructive positio-ns respectively.

Figure 6 is anelevation, partly in section, of a portion of the improved exible drive, and

Figure 10 is a similar sectional elevationto Fig. 3 of the working'head of the tool fitted with a reciprocating operative member, and

Figure 11 is a section on the line XI-XI in Fig. 10.

Referring iirst to Figs 1 to 5 of the drawings, the percussive tool therein illustrated has a working head Ill comprising a cylinder I5 provided with a flange IB and united by a screw thread Il to an extension I8 which is provided with a close-fitting cylindrical cap I9 encircled by a cover 23. The rear end of the cylinder I5 is embraced by the sleeve 2I of a handle V22, said sleeve being fitted onto said cylinder.

A. piston 23 is reciprocated within the cylinder I5 by a exible cable 24 having attached to it a ball-headed nipple 25 which is retained in a cavity in the piston by a ferrule 26 screwed into the rear end of the piston, which arrangement permits the cable to rotate independently of the piston, or vice versa. A helical compression `spring 21 is interposed between the piston 23 and a washer 'Il at the rear end of the handle (Fig. 8), the gcable 24 extending through the spring.

The forward end 28 of the piston 23 has a marginal surface 29 which is not subjected to the wear on the piston resulting from its use as a hammer, and a control ring 3l) is arranged to co-act with said marginal surface. The ring is moved transversely in the working head between the forward end of the cylinder I5 and the opposite face of an internal recess 3| in its extension I8. The ring is interposed between a pair of diametrically opposite balls 32, 33, the upper ball 32 being pressed downwards by a light spring 34 housed in a socket 35 partly in the extension I8 and partly in a linger piece 36 attached to the extension by a screw 31. The finger piece engages a deep axial notch 38 in the cap I9 and prevents rotation of the latter. When the control ring 30 is in its obstructive positionas shown in Figs. 3 and 4, the lower Figure 7 is an elevation, also partly in secv Y' tion, of the preferred power-driven reciprocating ball 33 rests in a socket 39 in the lower portion of the cap i9. Movement of the cap to the right is limited by an external shoulder 40 around the rear end of the extension I8, and its movement to the left is limited by the head of a check screw 4I in said extension co-acting with a slot I2 in the cap. An expanding split ring i3 may be provided in a groove around the extension to bear on the internal periphery of the cap and exert suiiicient frictional pressure thereon to prevent the cap sliding freely on the extension.

lThe shank of a drilllor chisel or other percussive operative member with which my tool is used is inserted into a holder 44 which can slide in the extension I8. A grooved collar 45 tight on the holder bears against a shoulder 46 therearound, and a light helical spring 41 is provided between the collar and the bottom of a groove `43am l'thefaend ofthe extension. The anged-end"49 of the "cap I9 Y'engages the Acollar 45 and limits the projection of the holder 44 under the pressure of the spring 41.

Fig. '1 shows, by way of example,v -a powerdriven reciprocating mechanism consisting o'f a swash plate B mounted on thezshaftvofriancelectric motor 5I. The ball 52 of the swash Aplate engages a socket 53 in the endpf aihollow Lpiston 54 working in a cylinder 55 secured 'by anut 56 and a set screw 51 in the back plate 58 of the casing of the mechanism. The casinghas'afre-n movable cover 59 provided with an inlet tted :with a .lscrew .-plugi ffor admissionof ilubricating aoil. :Alubricating nippleil isifittedinthe prov:the iend of `:said l'piston `and to fallow :said ferrule `Ihead iis liheld stationary vflcy the fcontrol 'ringil 'The `cable :passes 'through the extension '52 finto a flexible tube 185i; ithe fendiof whichisfas lshown 4afthreadedispigotillonvabush Bfree to revolve in a bearingfsin the'end of the fextension'there- "by allowing fthe-.tube 65fto irevolverelatively to thefcablelil. "The iiexible ftube Yis-fo'f lstout construction, fbeingcomposediof :material :capable of sustaining `leng'tlfxwise compression, fand is :maintained ipartiallyfcharged with 'lubricant lthroughout its 1:length by Taisupply-of Voil 'ini'ected through the nipple 3l.. The cable C24 recinrocates in 'a sheath 1U the ends of which terminate in sockets `lwithin-*thelends 'of the vtu'be1'65. The other'end 'of thefeXible-tube isas fshowniin-"Fi'g, f8, secured by Ialock -nut '11| 'screwed' onto one "end of la 4threaded*flanged:spi'gcitll theother lend 13 of @16 supporting 'the plug is inserted between the rear end o "thefs'leeve 2I :of the handle'and the rear -en'd fofthe `Vcylinder-I5; 'The rear end of Sthefhelifal=sprinfr ibears on Vawasher 11 abutting; .Y

against :an internal flange l13 at thef-rear Aend of the -cylinder I5. y

-Itwillbe seenthatthe le'ftward strokes of the Apiston vEsi are transmitted "by Y'the-cable 24 vto the piston `323-in Afthe working head I4 "to move 'the latter `piston to 'thefrigh'tto compress the spring 21, fand "that,Y during the '-rig'htward 'strokes of -th'e piston 54, the spring2'1providesthe'return- Lextensiorrll vand carries the collar with 'it against vthe slightresistance of the spring 41.

Afterv a shortv initial movement,` the collar -engages the inwardly flanged end 49 ofthe #cap I9 and slides lit vto the-right causing ythecam- 1 surfaced forward edge of the socket 39 in said cap to engage and raise the lower ball 33 and hence the control ring 30 against the pressure of the spring 34 into the position shown in Fig. 5 in which the ring is concentric with the body of the piston 23. The piston is then free to recipiroc'aterthrou'gh the ring1under-theaction of the 'spring'21'and cable 24, theehd 28 of the piston striking the opposed end 44a of the tool holder .x44 and providing a hammer drive to the operative .member therein. The cap I9 holds the ring in 'its concentric unobstructed position while the operativememberfin the tool holder 44 is pressed against the work. On said member being completelyremovedirom the work, the piston, by -impelling the holder 44 to the left, causes the collar 45 to pick up and return the cap I9 to its original position, thereby allowing the balls 32, 33 and the ring 3i), under the pressure of the V.spring 3421120 return :to the position shown inFigs.

:Ssand ijn-whichithefringis eccentric to the pis- .toni :and the forward .'reciprocation of Vthe latter isagain :obstructed VThe fspringfl' retains thezholderkin the ioi "position until theoperativegmember therein is -again .forcibly pressed :against its work. .Surface-friction between rthe pap 'i951 and the ,':expanding ksplit :ring y43 'in the extension IS prevents vthe lcap returning to the Voir position :should vthere `be Aany relaxation -of pressure fduring the application fof said operative member :to the work, ithe'fdegree of lost motion :allowed 'betweenrithe holder'M and the rcap vI9 A:enables said imember .tovibrate Withoutaiecting 'thecontrolmeans Normally the handle i22 is free to irotate relatively :to "the Vanged plug :15 onY the threaded spigot 1:3,'but the handle .can Abe 'locked to said :plug by thexengagjernent lof the "turned-'up end TIS of 'an arm '83 with anyone .of Vanumber of notches BI around .the lperiphery of the plug. The arm "8B is iixedby arivet 82 on the end of fa'ithreaded `rod -83linfa`hole 84 in 'the hand1e'22, the 'rod engaging 'an internally-threaded bush '85 vin said hole and afspring 86 being inserted between'the arm-80 and thefbush'. If the piston -23 requires toberadjusted, this can be effected by yrevolving the -rod 183 "by means of its milled head -81 to allow thesprin'g '86 to push the arm V8il'upwards until itsfend 19 engages one vof the notches TSI in the ange of the Yplug'15 whereupon the plug is locked to the handle 22 and the latter can 'be held to allow rotation of the adjustingvnut-'l-a to trave'lthespigot 12,13 on the cable. The provision of the ball bearing 16 permits the V'handle 22 and working head I4to revolve freely relatively to the ilexibe tube 65 and cable 24.

Figs. l0 and 11 villustrate a slightly modified construction wherein the working head I4a has a hollow piston 23a which receives A'the vtang Aor shank of a reciprocating operative member such as -a saw, 1shearing blade, punch or le. The extension I8@ yof the-cylinder I 5a of the working head is provided with a conical-nosed cap 8B securedto it'by a screw '89.7' 'lh'e'n'ose of the cap is ttedwiiih hand Yshield is aperture?? at "Si to lform-a guide for'the operative member carriedby the hollow piston 23a. The ball-headed `nipple 25 lof the cable 24 is introduced from the forward end of the piston land vbears in'a cup 93 fintherear end thereof. The control ring 30 cofacts with a peripheral groove 23a around the piston 123a and is interposed between balls 3 2 and 33a, the upper-"ball'beingpressed rdownwards by-'a light spring 34a housed 'in a socket35a'inthe extension |88. A rotatable cover '20e with a milled circumference encircles the extension and retains the spring 3l#EL and lower. ball 331I in position. When the control ring 30 is in its normal position as shown in Figs. and 11, its upper portion engages the groove 29a in the piston 23B and obstructs the reciprocation of the piston, the lower portion of the ball 33i projecting through an aperture 94 in the cover 20a. Finger pressure may be applied to the ball 33a to raise the control ring against the pressure of the spring 34a out of the groove in the piston into its nonobstructive position, whereupon the spring 21 and cable 24 co-operate to reciprocate the` piston 23a, but usually the control ring 30 is moved into its non-obstructive position by partially rotating the cover 2l)a to move its aperture 94 around so that the cover maintains the control ring against the pressure of its spring.

It will be seen that, by this invention, I provide a working head provided either with a percussive operative member or with a reciprocating operative member, said working head in each case having an apertured control member comprising a resiliently mounted ring co-acting with a piston operated by a cable reciprocated within a tube and forming a ilexible drive between said piston and the piston of a separated powerdriven reciprocating mechanism. Either working head can be coupled to the reciprocating mechanism.

It is obvious that various modifications within the principle and scope of my invention may be made in the constructions shown in the drawings and particularly described herein.

What I caim and desire to secure by Letters Patent in the United States of America is:

l. A portable tool having a working head including a cylinder, a tool operating piston -in said cylinder, a compression spring within the cylinder acting to urge the piston in one direction, a power-driven reciprocatory mechanism driving said piston, a resiliently mounted transversely movable apertured control member disposed within the cylinder and normally yieldably held eccentric to the piston to prevent a full working stroke of the piston, means for moving said control member transversely into concentricity with the piston to permit the latter to operate through the aperture of the control member, said means including a casing carried by and ymovable relatively -to the working head and disposed externally of said control member, and a member interposed between said casing and the external periphery of said control member coacting with the casing to transmit movement to the control member.

2. A portable tool having a working head including a cylinder, a tool operating piston in said cylinder, a compression spring within the cylinder acting to urge the piston in one direction, a power-driven reciprocatory mechanism driving said histon, the working head being provided with cylinder coacting endwise with said recess, means for moving said control ring transversely into concentricity with the piston to permit the latter to operate through the control ring, said means including a casing carried by and movable relatively to the working head and disposed externally of the control ring, and a ball interposed between said casing and the external periphery of the control ring coacting with said casing to transmit movement to the control ring, and a resiliently mounted ball interposed between said casing and the external periphery of the control ring and disposed opposite to said rst mentioned ball, said resiliently mounted ball acting to normally yieldably hold the control ring eccentric to the piston to prevent a full working stroke of the same.

3. A portable tool having la working head including a cylinder, a tool operating piston in said cylinder, a compression spring within the cylinder acting to urge the piston in one direction, a power-driven reciprocatory mechanism driving said piston, the working head being provided with a peripheral recess extending around said piston, a resiliently mounted transversely movable apertured control member disposed within the cylinder and normally yieldably held eccentric to the piston to prevent a full Working stroke of the piston, means for moving the control member into concentricity with the piston comprising a cap surrounding the forward end of said cylinder, a holder for a percussive operative member sliding in the forward end of the cylinder, a coupling between said holder and said cap to transmit the axial movement of the holder to said cap While permitting the holder to vibrate in operation, and means interposed between said cap and the external periphery of said control member for transmitting movement from the cap to the control member.

4. A portable tool as dened in claim 1 wherein the movable casing carried by the working head is rotatable to transmit movement to the means interposed between the casing and the external periphery of the control member to move the control member transversely into concentricity With the piston.

WILLIAM HENRY DEAN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,220,195 Amundsen Nov. 5, 1940 2,385,439 Gubbins Sept. 25, 1945 2,438,777 Dean Mar. 30, 1948 2,442,140 Mohr May 25, 1948 

